Tove Jansson's first ever Moomins book, a quest to find the lost Moominpappa which has never been published in the UK before, is set for release next month.

Written in 1945, The Moomins and the Great Flood sees Jansson using a mix of sepia washes and pen and ink line drawings to tell the story of Moominmamma and young Moomintroll's hunt for the long lost Moominpappa "through forest and flood". On the way, they meet a little creature – an early version of Sniff – and what publisher Sort Of Books described as "the elegantly strange Tulippa".

The translation, by David McDuff, was published in Finland in 2008, but will be released in the UK for the first time on 1 November. "We delayed the UK publication as we wanted to launch it in the approach to Tove Jansson's centenary year (2014) and did our best to make it a lovely possession," said publisher Natania Jansz. "I now wish we had similar works for all our great children's titles – the earliest Pooh, or Alice. It offers such a fascinating insight into the creative process."

Jansz called the book "a revelation … showing how Jansson's ideas and artworks evolved as she developed the Moomin themes and series".

"Written in the dark days of war – and as an escape from them – she uses a mixture of beautiful sepia and ink washes and pen and ink line drawing," she said. "It would take another decade before the Moomins could burst into full colour with The Book About Moomin, Mymble and Little My."